Suspensions of solid particles in liquids have considerable industrial importance and are utilized for different purposes to an ever increasing extent. One area in which such suspensions are used is the manufacture of sanitary goods, such as for example hand basins and WC pedestals. Such products are customarily manufactured by introducing a clay suspension into a mold which is fitted with porous walls. Water is absorbed by the walls of the mold and the clay, in this manner, forms a deposit or layer on the walls, whereupon the clay article is dried and fired. Another area of application for suspensions of solid particles in liquids is in the paper industry in which kaolin or other substances of small particle size are added to the pulp or to the paper sheet as fillers or coatings to impart the paper with a smooth surface. Still another field of application is in the paint industry in which certain paint compositions contain color pigments and colloidal organic binders suspended in an aqueous phase. Suspensions of solid particles in liquid are also used in the manufacture of so-called magnetic liquids, to wit, liquids which contain small magnetic particles and which behave as if they were homogeneous and magnetic. More recently suspensions of the indicated kind have been used in the electrical and electronic industries. The present invention is applicable to all fields of utilization for such suspensions of solid particles in liquids.
It has previously been suggested to utilize thermotropic liquid crystals in the manufacture of stable suspensions of solid particles. Thus, for example, J. Rault et al, Physics Letters, Vol. 32A, No. 3 of June 29, 1970, discuss suspensions of magnetic particles in thermotropic crystals. The suspending effect of thermotropic crystals is based on the high viscosity of such crystals whereby relatively stable suspensions of solid particles can be obtained. In other words, the mechanism of suspension which is involved is an increased Stokes viscosity and reduced sedimentation rate.